Lost Circulation Material for Reservoir Section

ABSTRACT

Loss circulation material (LCM) and method for treating loss circulation in a wellbore in a subterranean formation, including placing the LCM having a solid body with permeable portions or pores into the wellbore to dispose the LCM at the loss circulation zone, and collecting solids onto the LCM at the loss circulation zone to form a barrier. The LCM may be applied at a loss circulation zone in a hydrocarbon reservoir section of the subterranean formation, and upon subsequent hydrocarbon production the collected solids may be dislodged by the produced hydrocarbon to allow for hydrocarbon production through the permeable portions or pores of the disposed LCM.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a divisional of and claims the benefit of priorityto U.S. patent application Ser. No. 16/991,817, filed on Aug. 12, 2020,the contents of which are incorporated by reference herein.

TECHNICAL FIELD

This disclosure relates to lost circulation material (LCM) for curingloss circulation in a wellbore in a subterranean formation.

BACKGROUND

In oil or gas well drilling, loss circulation occurs when drilling fluid(mud) or cement slurry flows into the subterranean formation instead offlowing up the annulus between the formation and the casing or workstring. Loss circulation is the partial or complete loss of drillingfluid or cement slurry to the formation during drilling or cementingoperations. Loss circulation can be brought on by natural or inducedcauses. Natural causes include naturally fractured formations orunconsolidated zones. Induced losses occur when the hydrostatic fluidcolumn pressure exceeds the fracture gradient of the formation and theformation pores break down adequately to receive rather than resist thefluid. For non-cavernous formations, a loss circulation zone may be theresult of fractures in the geological formation at the borehole orwellbore. When loss circulation occurs, both drilling fluid and cementslurry can be lost. Loss circulation material (LCM) is a name forsubstances added to drilling fluids when drilling fluids are being lossdownhole to the subterranean formation. The LCM may be fibrous (e.g.,tree bark, shredded cane stalks, mineral fibers, and animal hair), flaky(e.g., mica flakes and pieces of plastic or cellophane sheeting), orgranular (e.g., ground and sized limestone, carbonates or marble, wood,nut hulls, Formica, corncobs, or cotton hulls). LCM may be introducedinto a mud system to reduce or prevent the flow of drilling fluid into apermeable formation.

SUMMARY

An aspect relates to a method of treating loss circulation in a wellborein a subterranean formation. The method placing loss circulationmaterial (LCM) having pores into the wellbore, and flowing the LCM todispose the LCM against the subterranean formation at a loss circulationzone in the wellbore. The method includes flowing wellbore fluid fromthe wellbore through the pores into the subterranean formation. Themethod includes collecting solids onto the LCM from the wellbore fluidflowed through the pores to form a barrier to treat the loss circulationat the loss circulation zone.

Another aspect relates to a method of treating loss circulation in awellbore in a subterranean formation. The method positioning LCM objectsat a loss circulation zone in the wellbore at a hydrocarbon reservoirsection of the subterranean formation, wherein the LCM objects havepermeable portions. The method includes flowing wellbore fluid from thewellbore through the permeable portions into the subterranean formation,and collecting solids from the wellbore fluid onto the LCM objects tostop or reduce flow of the wellbore fluid through permeable portionsinto the subterranean formation.

Yet another aspect relates to LCM that is a plurality of LCM objects,each LCM object of the plurality having a solid body with permeablesections including pores, wherein the plurality to arrange at a losscirculation zone in a wellbore in a subterranean formation to allowwellbore fluid to flow through the pores into the subterraneanformation, and the plurality to collect solids from the wellbore fluidto form a flow barrier.

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features andadvantages will be apparent from the description and drawings, and fromthe claims.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1-3 are diagrams of loss circulation material (LCM) objects.

FIG. 4 are diagrams of LCM objects as arranged.

FIG. 5 is a diagram of a well site.

FIG. 6 is a block flow diagram of a method of treating loss circulationin a wellbore in a subterranean formation.

FIG. 7 is a block flow diagram of a method of treating loss circulationin a wellbore in a subterranean formation.

FIG. 8 is a method of applying LCM to a wellbore in a subterraneanformation.

DETAILED DESCRIPTION

Some aspects of the present disclosure are directed to loss circulationmaterial (LCM) having sections that are porous and permeable. Thesections may be part of a solid body and formed in grooves of the solidbody. The LCM may be flaky LCM. The LCM may be applied to treating losscontrol (loss circulation) in a pay zone (hydrocarbon reservoirsection). Therefore, as discussed below, the LCM may be characterized asreservoir friendly. The LCM may be applied to loss circulation zoneshaving permeable features of the subterranean formation in a hydrocarbonreservoir section of the subterranean formation. The permeable featuresin the subterranean formation may be highly permeable. In one example,the highly permeable features may be labeled as a super-k zone capableof producing at least 500 barrels per day per foot of thickness. Thepresent flaky LCM are applicable to permeable zones in the formationthat cause loss circulation, such as during drilling, but where thepermeable zones would provide for hydrocarbon production during thesubsequent production phase.

In certain cases, drilling fluid employed in a hydrocarbon reservoirportion of the subterranean formation may be labeled as drill-in fluid.Drill-in fluid can be drilling fluid configured for drilling a boreholein a reservoir section, e.g., with intent to reduce damage to theformation and increase subsequent production of hydrocarbon. In someimplementations, drill-in fluid can resemble a completion fluid. Adrill-in fluid may include additives beneficial for filtration controland also carrying of rock cuttings, and the so forth.

Some embodiments relate to a flaky LCM having porous sections that maybe part of a solid body, residing or formed in grooves or channels ofthe solid body. The flaky LCM is permeable to hydrocarbon flow from thesubterranean formation into the wellbore through the porous sections.The flaky LCM can have a cube shape or other shapes and be made ofpolymer such as via additive manufacturing or three dimensional (3D)printing. In application, the flaky LCM are provided to the losscirculation zone in the wellbore (e.g., at a hydrocarbon reservoirsection of the subterranean formation). Initially, drilling fluid flowsthrough the flaky LCM porous portions into the subterranean formation.However, the pores are generally smaller than at least some of thesolids in the drilling fluid. Consequently, solids (e.g., fillermaterial, other LCMs, etc.) in the drilling fluid form a filter cake onthe flaky LCM on the wellbore side and thus stop flow of drilling fluidthrough the flaky LCM porous sections into the formation. Once drillingis complete and hydrocarbon production started, the wellbore pressure islower than the formation pressure. Therefore, produced hydrocarbon flowsfrom the subterranean formation through the flaky LCM porous sectionsdisplacing the filter cake (on the wellbore side). Production from thesubterranean formation may continue through the flaky LCM into thewellbore.

Conventional flaky LCMs are generally non-porous and impermeable. Hence,the mat or barrier formed by the flakes (conventional flaky LCM) in theloss zone of a reservoir section will generally permanently seal andblock the highly-conductive fluid channels of the loss zones that wouldbe beneficial to enhance well productivity. Conventional flaky LCM canhave a significant detrimental impact on productivity of a well becausethe LCM obstructs permeable features (e.g., fractures, super-k channels,etc.) of the subterranean formation at the reservoir section.

In contrast, embodiments of the present flaky LCMs having porous andpermeable channels that are smaller than the drill solid particles ofthe mud system may generally prevent or reduce the loss of whole mudwhile drilling but allow the production of hydrocarbon after completinga well. Embodiments of the present techniques include reservoir-friendlyflaky LCMs containing porous and permeable channels that are smallenough to prevent the loss of whole mud while drilling but large enoughto allow the production of hydrocarbon after completion of a well.Embodiments of the present flaky LCM may be manufactured by additivemanufacturing via a 3D printer. Other applicable manufacturingtechniques may include, for example, casting (cast molding), injectionmolding, or compression molding. The manufacturing technique selectedfor implementation may be in response to LCM technical specificationsfor particular applications of the LCM.

FIGS. 1-3 are examples of the present LCM, which may be flaky LCM orflake LCM. Flaky or flake LCM can be LCM objects having a relativelylarge ratio of surface area to volume. Flaky LCM can generally beinsoluble to the mud system (drilling fluid or carrier fluid) in whichthe flaky LCM is employed. Flaky LCM can be utilized to seal fluid losszones (loss circulation zones) in a well (wellbore) to aid in stoppingor reducing lost circulation. Flake LCM can be applied in an LCM pilland pumped into the wellbore section where loss circulation isoccurring. Other LCM types (e.g., granular, fiber, etc.) may be employedin the LCM pill with the flaky LCM.

FIGS. 1-3 each give a perspective view and approximate orthographicviews of an LCM object of the present LCM. These examples of the presentLCM objects depicted may be utilized in a plurality of the same orsimilar present LCM objects to give the LCM to treat loss circulation.The solid body 110, 210, 310 of the LCM object 100, 200, 300 in FIGS.1-3, respectively, is a rectangular cuboid shape. Other embodiments ofthe LCM object have a solid body with a shape different than rectangularcuboid. The solid body can be a sphere, spheroid, ovoid, cuboid,rectangular cuboid, hyperrectangle, a pentahedron, or an irregularshape, and so on.

In FIGS. 1-3, the permeable sections 112, 212, 312 are elongated havinga length substantially greater than their width. The length of thepermeable sections 112, 212, 312 may depend on the size (e.g., distanceor area) of the sides of the solid body 110, 210, 310. The permeablesections 112, 212, 312 may generally run across the respective side. Thewidth of the permeable sections 112, 212, 312 may be, for example, lessthan 1 mm or less than 0.5 mm. The permeable sections 112, 212, 312 havea depth into the solid body 110, 210, 310, such as less than 4 mm, lessthan 3 mm, or less than 2 mm. A difference generally between therespective LCM object 100, 200, 300 of FIGS. 1-3 is orientation of thepermeable sections with regard to the solid body 110, 210, 310.

FIG. 1 is the LCM object 100. Depicted are a perspective view 102, topview 104, front view 106, and side view 108. The LCM object 100 includesa solid body 110 having permeable sections 112 that include pores 114.In the illustrated example, the permeable sections 112 on four sides maybe characterized as having a vertical orientation with respect to agiven top and bottom (the remaining two sides). As mentioned, the solidbody 110 is a rectangular cuboid in the illustrated embodiment. Forimplementations for the solid body 110, the length is in the range of 5mm to 20 mm, or less than 30 mm, and the height and width are each inthe range of 3 mm to 10 mm, or less than 10 mm. In one example, theL×H×W of the solid body 110 is 12 mm×5 mm×5 mm.

The illustrated example of the solid body 110 has two sides designatedas top 116 (top view 104) and bottom 118, respectively, for reference(given or assigned) so to label the orientation (vertical in thisexample) of the permeable sections on the four remaining sides. In theillustrated embodiment, orientation of the permeable sections 112 on thefour remaining sides may be characterized as vertical from top tobottom. In this example, the four remaining sides include the front 120(front view 106), the back (not shown), and the two sides 122, 124 (sideview 108) not the front or back. In examples, the back may generally besimilar or identical to the front 120. In implementations, the two sides122, 124 may be the same or similar. The orientation or arrangement ofthe permeable sections 112 on the top 116 and bottom 118 may be asdepicted or as otherwise specified.

The number of permeable sections 112 at each of the top 116, bottom 118,front 102, and back may be at least 2, at least 3, at least 4, at least5, or at least 6. In the illustrated embodiment, this number is 5. Thenumber of permeable sections 112 for each of the two sides 122, 124 maybe at least 1, at least 2, at least 3, or at least 4. In the illustratedembodiment, this number is 3. The spacing between permeable sections 112on a given side may be, for example, less than 2.5 mm, less than 2 mm,less than 1.5 mm, less than 1 mm, or less than 0.5 mm. In theillustrated embodiment, this spacing is 1.5 mm on the top 116, bottom118, front 120, and back, and is 0.75 mm on the two sides 122, 124.

The permeable sections 112 of the solid body 110 may be permeableportions of the solid body 110, porous sections of the solid body 110,porous portions of the solid body 110, permeable structures of or withinthe solid body 110, porous structures of or within the solid body 110,and the like. The permeable sections 112 may be generally part of thesolid body 110 at or near the external surface of the solid body 110 andexposed to outside (external) of the solid body 110. The externalsurface of the permeable sections 112 may be an external surface of thesolid body 110. The permeable sections 112 may be formed in recessedvolumes such as grooves or channels. The exterior surface of thepermeable sections 112 with respect to the exterior surface of theremaining part (portion) of the solid body 110 may be recessed, flushed(even), or protruding. As shown, the permeable sections 112 areelongated having a length substantially greater than their width. Asdiscussed, the width of the permeable sections 112 may be, for example,less than 1 mm or less than 0.5 mm. The permeable sections 112 have adepth into the solid body 110. The depth may be, for example, less than4 mm, less than 3 mm, or less than 2 mm. The depth for the permeablesections 112 on the side 124 is indicated by reference numeral 126.

The permeable sections 112 on one side may meet (interface and overlap)with permeable sections 112 on another side at where the two sides meet(at the edge between the two sides). For instance, in the example ofFIG. 1, the permeable sections 112 on the front 120 meet the permeablesections 112 on the bottom 118 at the edge where the front 120 andbottom 118 meet. Such interface or overlap of permeable sections 112between sides may advance fluid flow through the LCM as arranged at aloss circulation zone.

In the aforementioned example with the solid body 110 having dimensionalvalues of 12 mm×5 mm×5 mm, the width of the permeable sections 112 is0.5 mm and the depth of the permeable sections 112 is 2 mm. For theimplementation depicted in FIG. 1, the number of permeable sections 112on each of the top 116, bottom 118, front 120, and back is 5 with aspacing of 1.5 mm, and the number of permeable sections 112 on each side122, 124 is 3 with a spacing of 0.75 mm.

For various embodiments, the pore size (e.g., width or diameter) of thepores 114 of the permeable sections 112 may be less than 100 microns,less than 50 microns, or less than 10 microns. The pore size may bespecified to be less than the particle size of at least some of thesolids in the wellbore fluid in the wellbore having the loss circulationzone being treated.

FIG. 2 is an LCM object 200 similar to the LCM object 100 of FIG. 1, butwith a different orientation of permeable sections. FIG. 2 gives aperspective view 202, top view 204, front view 206, and side view 208 ofthe LCM object 200. The LCM object 200 includes a solid body 210 havingpermeable sections 212 including pores 214. In the example of FIG. 2,the permeable sections 212 on four sides may be characterized as havinga horizontal orientation with respect to a given top and bottom(remaining two sides). The solid body 210 is a rectangular cuboid in theillustrated embodiment. In implementations, the solid body 210 may havethe same or similar values for L×W×H dimensions as the solid body 110 ofFIG. 1. The illustrated example of the solid body 210 has two sidesassigned as top 216 and bottom 218, respectively, for reference (given)for labeling the orientation (horizontal in this example) of thepermeable sections 212 on the four remaining sides. In the illustratedembodiment, orientation of the permeable sections 212 on these fourremaining sides may be characterized as horizontal with respect to thetop 216 and bottom 218. In this example, the four remaining sidesinclude the front 220, the back (not shown), and the two sides 222, 224not the front or back. In examples, the back may generally be similar oridentical to the front 220. In implementations, the two sides 222, 224may be the same or similar. The orientation or arrangement of thepermeable sections 212 on the top 216 and bottom 218 may be as depictedor as otherwise specified.

The number of permeable sections 212 at each of the front 220, back, andtwo sides 222, 224 may be at least 2, at least 3, at least 4, at least5, or at least 6. In the illustrated embodiment, this number is 5. Thenumber of permeable sections 212 for each of top 216 and bottom 218 maybe at least 1, at least 2, at least 3, or at least 4. In the illustratedembodiment, this number is 3. The spacing between permeable sections 212on a given side may be, for example, less than 2.5 mm, less than 2 mm,less than 1.5 mm, less than 1 mm, or less than 0.5 mm. In theillustrated embodiment, this spacing is 1.5 mm on the front 220, back,and two sides 222, 224, and is 0.75 mm on the top 216 and the bottom218.

The permeable sections 212 of the solid body 210 may be permeableportions, porous sections, porous portions, permeable structures, porousstructures, and the like. The width or diameter of the pores 214 (e.g.,same or similar to pores 114) may be, for example, less than 100microns, less than 50 microns, or less than 10 microns. As with thepermeable sections of FIG. 1, the permeable sections 212 may begenerally part of the solid body 210 at or near the external surface ofthe solid body 210 and exposed to the outside (external) of the solidbody 210 exterior. While the permeable sections 212 may be part of thesolid body 210, the permeable sections 212 may be formed or reside ingrooves or channels of the solid body 210. The exterior surface of thepermeable sections 212 may be recessed, flushed (even), or protrudingwith respect to the exterior surface of the remaining part (portion) ofthe solid body 210. The elongated permeable sections 212 may have thesame or similar dimensional (width, depth) values as the permeablesections 112 of FIG. 1. The depth for the permeable sections 212 on thebottom 218 is indicated by reference numeral 226. In one example, thesolid body 210 has L×W×H of 12 mm×5 mm×5 mm, and in which the width ofthe permeable sections 212 is 0.5 mm and the depth of the permeablesections 212 is 2 mm.

Referring to FIGS. 1 and 2, a combination or mixture of multiple LCMobjects 100 and multiple LCM objects 200 may be utilize togethercollectively as LCM to treat loss circulation. The LCM with LCM objectshaving differing respective orientations of the permeable sections mayadvance the intercoupling of the permeable sections for fluid flow therethrough with the LCM as arranged at the loss circulation zone. Thus theLCM may include a first set (group) of the flaky LCMs and second set(group) of the flaky LCMs with the first set having the same topdesignation as the second set, and wherein orientation of permeablesections in the first set is vertical from top to bottom, andorientation of permeable sections in the second set is horizontal withrespect to top and bottom. Similarly, in examples, for a first group andsecond group of the flaky LCMs having the same top designation, theorientation of permeable sections in the first group is 90° differentthan the orientation of permeable sections in the second group.

For LCM having a collection or plurality of LCM objects including LCMobjects 100 and LCM objects 200, embodiments can be characterizedwithout specifying a top or bottom in particular for reference butinstead noting a given side. For instance, for a given side in a firstgroup (LCM objects 100) and second group (LCM objects 200) of the flakyLCMs, the orientation of the permeable sections 112 in the first groupis substantially perpendicular to the orientation of the permeablesections 212 in the second group. Lastly, it should be noted in someexamples with the solid body 110, 210 having the same dimensions andwith L=W=H, the LCM object 100 and LCM object 200 may not be differentor distinguishable.

FIG. 3 is an LCM object 300. Depicted are a perspective view 302, topview 304, front view 306, and side view 308. The solid body 310 is arectangular cuboid. The LCM object 300 includes the solid body 310having permeable sections 312 including pores 314. The permeablesections 312 on four sides may be characterized as having a slantedorientation (not horizontal and not vertical) with respect to a giventop and bottom (remaining two sides). The permeable sections 312 on allsix sides may be characterized as having an orientation that is parallelwith a diagonal on the respective side. In implementations, the solidbody 310 may have the same or similar values for L×W×H dimensions as thesolid body 110 of FIG. 1 and the solid body 210 of FIG. 2. Theillustrated example of the solid body 310 has two sides assigned as top316 and bottom 318, respectively. The four remaining sides include thefront 320, the back (not shown), and the two sides 322, 324 not thefront or back. The back side may generally be similar or identical tothe front 320. In implementations, the two sides 322, 324 may be thesame or similar.

In the example of FIG. 3, the number of permeable sections 312 at eachof the front 320 and the back may be, for example at least 4, at least5, at least 6, at least 7, or at least 8. In the illustrated embodiment,this number is 7. The number of permeable sections 312 for each of top316, bottom 318, and the two sides 322, 324 may be, for example, atleast 3, at least 4, at least 5, or at least 6. In the illustratedembodiment, this number is 5. The spacing between permeable sections 312on a given side may be, for example, less than 2.5 mm, less than 2 mm,less than 1.5 mm, less than 1 mm, or less than 0.5 mm. In theillustrated embodiment, this spacing is about 1 mm.

As indicated with respect to preceding figures, the permeable sections312 of the solid body 310 may be permeable portions, porous sections,porous portions, permeable structures, porous structures, and the like.The width or diameter of the pores 314 (e.g., same or similar to pores114 and pores 214) may be, for example, less than 100 microns, less than50 microns, or less than 10 microns. As with the permeable sections ofFIGS. 1-2, the permeable sections 312 may be part of the solid body 210at or near the external surface of the solid body 310 and exposed to theoutside (external) of the solid body 310 exterior. While the permeablesections 312 may be part of the solid body 310, the permeable sections312 may be formed or reside in grooves or channels of the solid body310. The exterior surface of the permeable sections 312 may be recessed,flushed (even), or protruding with respect to the exterior surface ofthe remaining part (portion) of the solid body 310. The elongatedpermeable sections 312 may have the same or similar width and same orsimilar depth as the permeable sections 112 of FIG. 1 and permeablesections 212 of FIG. 2. In one example, the solid body 310 has L×W×H of12 mm×5 mm×5 mm, and in which the width of the permeable sections 312 is0.5 mm and the depth of the permeable sections 312 is 2 mm.

Referring to FIGS. 1-3, a combination or mixture of multiple LCM objects100, multiple LCM objects 200, and multiple LCM objects 300 may beutilize together collectively as LCM to treat loss circulation. The LCMwith LCM objects having differing respective orientations of thepermeable sections may advance the intercoupling of the permeablesections for fluid flow there through within the LCM as arranged at theloss circulation zone. The LCM may include a first set (group) of theflaky LCMs, second set (group) of the flaky LCMs, and a third set(group) of the flaky LCMs with the first set, second set, and third sethaving the same top designation, and wherein orientation of permeablesections in the first set is vertical from top to bottom, orientation ofpermeable sections in the second set is horizontal with respect to topand bottom, and orientation of permeable sections in the second set isslanted (not horizontal and not vertical) with respect to top andbottom. The orientation of permeable sections on the four sides (not thetop and bottom) for the LCM objects in the first group may be 90°different than the orientation of permeable sections on the respectivefour sides (not the top and bottom) for the LCM objects in the secondgroup. The orientation of permeable sections for the LCM objects in thethird group for a given (corresponding) side may be 45° different thanthe orientation of permeable sections in the first and second groups forthat given (corresponding) side.

For LCM having a collection or plurality of LCM objects including LCMobjects 100 (first group), LCM objects 200 (second group), and LCMobjects 300 (third group), embodiments can be characterized withoutspecifying a top or bottom in particular for reference but insteadnoting a given side. For instance, for a given side in the first group(e.g., LCM objects 100) and the second group (e.g., LCM objects 200) ofthe flaky LCMs, the orientation of the permeable sections 112 in thefirst group is substantially perpendicular to the orientation of thepermeable sections 212 in the second group. For that given side, theorientation of the permeable sections 312 in the third group (e.g., LCMobjects 300) is 45° different than the first group and the second group.In other words, for the given side in the third group of the flaky LCMs,the orientation of the grooves is about 45° with respect to theorientation in the first and second groups.

FIG. 4 is random arrangements 400 of flaky LCM objects 402. Threedifferent random arrangements (a), (b), and (c) are depicted. The flakyLCM objects 402 may be analogous to the LCM object 100, LCM object 200,or LCM object 300, or any combinations thereof. The flaky LCM objects402 may randomly arrange at a loss circulation zone. In someimplementations, the loss circulation zone may be in a hydrocarbonreservoir section of the subterranean formation. The flaky LCM objects402 may randomly arrange at, in, or over features (e.g., permeableportions, fractures, etc.) of the subterranean formation that contributeto loss circulation.

The LCM objects 402 as randomly arranged may allow wellbore fluid toflow through permeable sections (as intercoupled) of the LCM objects 402into the subterranean formation. The pores of the permeable sections maybe smaller than solids in the wellbore fluid. Therefore, the LCM objects402 may collects solids from the wellbore fluid to form a flow barrieron the LCM objects 402 to stop or reduce flow of wellbore fluid (ordrilling fluid) into the subterranean formation. A filter cake of thesolids may form on the wellbore side of the LCM objects 402.Subsequently, when production of hydrocarbon (e.g., crude oil, naturalgas, etc.) from the subterranean formation into the wellbore isinitiated, the hydrocarbon may dislodge the collected solids or filtercake. Thus, the hydrocarbon may be produced through the permeablesections of the LCM objects 402 with the LCM object 402 remaining inplace. In instances, some or majority of the LCM objects 402 may bedisplaced by the hydrocarbon.

Loss circulation may occur in drilling or cementing operations. In adrilling operation, drilling fluid may be pumped via mud pumps into awellbore through a drill string to a drill bit (at the bottom of thewellbore) that breaks rock to drill the borehole. The drilling fluid maydischarge from nozzles on the drill bit and flow back up through anannulus to Earth surface. The annulus may be between the wellbore wall(formation surface) and the drill string, or between the wellbore wall(formation) and wellbore casing in which the drill string is inserted.Some or all of the drilling fluid returning through the annulus to theEarth surface may be lost into the subterranean formation at the losscirculation zone in the wellbore.

In cementing, the cement slurry may be pumped from the Earth surfaceinto the wellbore down the interior of the casing and then upward fromthe bottom through the annulus between the casing and the formation.When the cement reaches the loss circulation zone, the cement does notadequately continue upward. The loss of cement slurries to such thiefzones can cause problems during cementing including resulting ininadequate amounts of cement slurry in the annulus between the casingand the subterranean formation. The inadequate amounts of cement slurrycould lead to poor zonal isolation during the subsequent production ofhydrocarbon from the subterranean formation through the wellbore to theEarth surface.

FIG. 5 is a well site 500 having a wellbore 502 through the Earthsurface 504 into a subterranean formation 506 in the Earth crust. Thesubterranean 506 may also be labeled as a geological formation,hydrocarbon formation, reservoir, etc. Hydrocarbon may be produced fromthe subterranean formation 506 through the wellbore 502 to the surface504. The hydrocarbon may be crude oil or natural gas, or both. To formthe wellbore 502, a hole (borehole) is drilled into the subterraneanformation 506 to generate a drilled formation surface 508 as aninterface for the wellbore 502 with the subterranean formation 506. Theformation surface 508 may be characterized as the wellbore 502 wall. Thewellbore 502 may have openhole portions but generally includes acylindrical casing 510 as shown. The wellbore 502 in the depictedimplementation of FIG. 5 is a cased wellbore 502. In the illustratedembodiment, the wellbore 502 has a loss circulation zone 512 caused byloss-circulation features 514 of the subterranean formation 506 at thatportion of the wellbore 502. The loss circulation zone 512 may be in ahydrocarbon reservoir section of the subterranean formation 506. Theloss-circulation features 514 along the wellbore 502 at the losscirculation zone 512 cause or contribute to the loss circulation. Theloss-circulation features 514 are structural features or characteristicsof the subterranean formation 506 at or near the wellbore 502. Thefeatures 514 may be fractures, voids, vugulars (vugs), gaps, permeablechannels, cavities, cavernous openings, etc. A vugular may be a cavityin subterranean rock and can be lined with mineral precipitates. Thefeatures 514 or feature 514 generally may be a permeable zone orunconsolidated portion of the subterranean formation 506. The losscirculation zone 512 may be a super-k zone capable of producing at least500 barrels hydrocarbon per day per foot of thickness.

In a drilling operation, drilling fluid (mud) introduced from thesurface 504 flowing downward through the casing 510 (and drill string)discharges from the drill bit (not shown) at the bottom of the wellbore502, and flows upward through the annulus between the subterraneanformation 506 and the casing 510 toward the surface 504 as returndrilling fluid. Some or all of the drilling fluid flowing upward throughthe annulus may be lost through the features 514 (e.g., permeable zoneor fractures) into the subterranean formation 506 at the losscirculation zone 512 in the wellbore 502.

For a cementing operation (e.g., primary cementing), the cement slurrymay be introduced from the surface 504 into the casing 510 in thewellbore 502 and discharges from the bottom of the casing 510. Thecement slurry then flows up through the annulus between the formation506 and the casing 510 toward the surface 504. The cement slurry flowingupward in the annulus may be lost through the features 514 into thesubterranean formation 506 at the loss circulation zone 512.

The present LCMs (e.g., FIGS. 1-4) discussed above may be utilized totreat the loss circulation zone 512 to cure the loss circulation. ThisLCM (having permeable sections) as randomly arranged at the losscirculation zone 512 may initially allow wellbore fluid to flow into thesubterranean formation 506 but collect solids from the wellbore fluid toform a flow barrier. The formed flow barrier may reduce or prevent flowof drilling fluid or cement slurry through the features 514 (e.g.,super-k zone) into the subterranean formation 506. The solids may beadded to the treatment fluid along with the present LCM objects or thesolids may added to the wellbore 502 after application of the presentLCM objects.

A treatment fluid 516 having LCM that includes multiple LCM objects 100,200, and/or 300 (FIGS. 1-3) or similar LCM objects may be introduced(e.g., pumped) into the wellbore 502. The treatment fluid 516 may bepumped by a surface pump (e.g., mud pump) of the surface equipment 518at the surface 504. In certain implementations, the pump may beassociated with a drilling rig. The pump(s) can be skid-mounted in someinstances. The pump may be a centrifugal pump, positive displacement(PD) pump, reciprocating PD pump such as a piston or plunger pump, andso on. The surface equipment 518 may include equipment (e.g., vessels,solid-handling equipment, piping, pumps etc.) to incorporate LCMobjects, viscosifier, and solids (e.g., filler material, bridgingmaterial, other LCM products, etc.) into the treatment fluid 516. Thesolids are in addition to present LCM objects. The surface equipment 518may include equipment to support other operations at the well site 500.

The treatment fluid 516 may be, for example, drilling fluid (mud) orcarrier fluid. The treatment fluid 516 may be oil-based or water-based.The treatment fluid 516 may include water, mineral oil, synthetic oil, aviscous additive (viscosifier), and so forth. The viscosifier may be,for example, bentonite, XC polymer, or starch for water-based treatmentfluid 516. The viscosifier may be, for example, organophilic clay foroil-based treatment fluid 516. The treatment fluid 516 may be labeled asa treatment slurry in that the treatment fluid 516 includes the presentLCM objects and optionally other solids. In implementations, thetreatment fluid 516 having the LCM objects 100 may be labeled orcharacterized as an LCM pill. In general, a pill may be a relativelysmall quantity or volume (e.g., less than 500 barrels) of drilling fluidor carrier fluid as a specified blend utilized for a particular purposein treating the wellbore 502 or subterranean formation 506.

The size and geometry of the present LCM objects included in thetreatment fluid 516 may be specified in response to (correlative with)size (e.g., cross-sectional area) or permeability of the features 514(e.g., permeable portion, fractures, gaps, channels, cavities, openings,etc.) of the subterranean formation 506 at the loss circulation zone512. The concentration of the LCM objects 100 in the treatment fluid 216may be, for example, in the range of 5 pounds per barrel (ppb) to 100ppb, or at least 30 ppb. Additional solids (not the LCM objects 100) ifincluded in the treatment fluid 216 may be, for example, as aconcentration of less than 100 ppb in the treatment fluid 216.

In the downhole application, the present LCM product (e.g., LCM objects100, 200, and/or 300) may randomly arrange at the features 514 to allowfor flow of wellbore fluid through permeable sections of the LCM andthus collect solids from the wellbore fluid onto the LCM. The collectionof solids may form a filter cake on the wellbore 502 side of the LCM togive a flow barrier in which flow may cease through the permeablesections from the wellbore 502 into the subterranean formation 506. Theformed flow barrier may cure the loss circulation at the losscirculation zone. Subsequently, when hydrocarbon production from thesubterranean formation 506 into the wellbore (to the Earth surface 504)is initiated, the flow of the hydrocarbon displaces the collected solids(e.g., filter cake). Thus, hydrocarbon production may flow through thepermeable sections of the LCM as applied and arranged at the features514. During production, the pressure of the subterranean formation 506is greater than pressure in the wellbore 502. Such may provide motiveforce of flow of the hydrocarbon production and removal (via thehydrocarbon flow) of collected solids in or on the wellbore side of theLCM.

As indicated, additional solids (e.g., less than 100 ppb) may be addedalong with the present LCM objects (e.g., also less than 100 ppb) to thetreatment fluid 516 at the surface 504. The combination of the presentLCM objects and the additional solids may be less than 200 ppb in thetreatment fluid 516. The added solids may include other LCM products asfiller solids that can be collected by the present LCM (e.g., LCMobjects 100, 200, and/or 300) to advance formation of the flow barrier.The added solids may generally include filler solids that may be labeledas filler material or bridging material. In application, the fillersolids as particles suspended in the treatment fluid 516 may becollected present LCM as random arranged at the lost circulation zone512. The filler solids may include small particles having, for example,an effective diameter less than 2 mm in effective diameter down tomicron scale (e.g., 100 microns). The filler solids may include volcanicash (generally non-swelling), bentonite (generally swelling), Rev Dust™(generally non-reactive), ARC Plug or Nut plug (both known as bridgingmaterial), and the like. A blend design may be implemented in which twoor more blends of the additives may be prepared in advanced, and thenadded to the treatment fluid 516 at the surface 504 at the time ofapplication. In some embodiments, a single sack for the LCM pill systemmay be implemented in which the present LCM objects and optionally otheraforementioned additives are pre-mixed and added to the drilling mud (orcarrier fluid) to give the treatment fluid 516. Such may save time, andaccelerate the mixing process and improve the slurry quality. Singlesack typically has all the components in one sack so that contents canbe mixed at the same time at the same rate by pouring a single sackinto, for example, the mud mixing hopper.

Embodiments of the present flaky LCM may be manufactured by additivemanufacturing via a 3D printer. The additive manufacturing may be, forexample, fused deposition modeling (FDM) or other types of 3D printing.For a fabrication system having the 3D printer, the computer modeldriving the 3D printer may be configured or set (programmed) to form LCMhaving the solid body (specified size) with permeable sections. Thenumber and placement of the permeable sections, as well as the poresizes, are specified. The 3D material may be polymer or metal. Thus, thepresent LCM (e.g., LCM objects 100, 200, 300) may be polymer or metal.Other applicable manufacturing techniques may include, for example,machining (subtractive manufacturing) or molding. Molding may include,for example, casting (cast molding), injection molding, or compressionmolding. The fabrication system may include, for example, an injectionmold, to receive a material (for example, a polymer) to form the LCMobjects 100, 200, 300. For the implementation of the fabrication systemhaving an injection mold, the mold may be shaped in the form of thesolid body (specified size) having permeable sections (number andplacement designated) with specified pore size. The manufacturingpractice selected for implementation may be in response to LCM technicalspecifications for particular applications of the LCM. The presentmethods disclosed herein may include fabricating the LCM objects via 3Dprinting or other techniques.

FIG. 6 is a method 600 of treating loss circulation in a wellbore in asubterranean formation. At block 602, the method includes placing LCM(e.g., flaky LCM) having pores into the wellbore. The LCM may havepermeable sections having the pores. The placing of the LCM into thewellbore may involve pumping fluid having the LCM into the wellbore. Thefluid may be, for example, drilling fluid (drilling mud) or carrierfluid. In some embodiments, concentration of the LCM in the fluid isless than 100 ppb. The fluid pumped into the wellbore may include solidsin addition to the LCM. The solids may include bridging material, fillermaterial, or other LCM product not the LCM, or any combinations thereof.

At block 604, the method includes flowing the LCM to dispose the LCMagainst the subterranean formation at a loss circulation zone in thewellbore. The flowing of the LCM may involve flowing the LCM to disposethe LCM at features of the subterranean formation that contribute toloss circulation at the loss circulation zone. The LCM may randomlyarrange at features of the loss circulation zone such that wellborefluid can initially flow through the LCM pores into the subterraneanformation. In certain implementations, the loss circulation zone is at ahydrocarbon reservoir section of the subterranean formation.

At block 606, the method includes flowing wellbore fluid from thewellbore through the pores into the subterranean formation. The flowingof the wellbore fluid through the pores may involve allowing loss ofwellbore fluid through the pores into the subterranean formation at theloss circulation zone. The wellbore pressure may generally be greaterthan the subterranean formation pressure. The wellbore pressure may beprovided via a surface pump.

At block 608, the method includes collecting solids onto the LCM fromthe wellbore fluid flowed through the pores to form a barrier (e.g.,flow barrier) to treat the loss circulation at the loss circulationzone. To treat the loss circulation may involve to stop or reduce flowof the wellbore fluid into the subterranean formation at the losscirculation zone. The flow of the wellbore fluid through the pores intothe subterranean formation may be stopped or reduced due to formation ofthe barrier. The pores may generally be smaller than the solidsparticles. The collecting of the solids may foul the pores. To form thebarrier may involve the collecting of the solids fouling the pores. Thecollecting of the solids may form a filter cake of the solids on awellbore side of the LCM. In implementations, the collecting of thesolids forms the barrier as a flow barrier across or over the pores. Thesolids may include, for example, bridging material, filler material, orother LCM product not the LCM, or any combinations thereof.

At block 610, the method includes producing hydrocarbon from thesubterranean formation. The hydrocarbon may be, for example, crude oilor natural gas, or both. The production of the hydrocarbon may involveflowing the hydrocarbon from the subterranean formation through the LCMpores into the wellbore. The flowing of the hydrocarbon through thepores removes at least a portion of the solids collected on the LCM.

FIG. 7 is a method 700 of treating loss circulation in a wellbore in asubterranean formation utilizing LCM that is multiple LCM objects (e.g.,flaky LCM). The LCM objects have permeable portions (e.g., havingpores). Each LCM object of the LCM objects may have a solid body havingthe permeable portions. In some examples, each solid body has at leastfive permeable portions. The LCM objects may be, for example, polymer ormetal. In some implementations, the method may include fabricating theLCM objects by additive manufacturing (3D printing).

At block 702, the method includes positioning the LCM objects at a losscirculation zone in the wellbore at a hydrocarbon reservoir section ofthe subterranean formation. The positioning the LCM objects may involveplacing the LCM objects from Earth surface into the wellbore and flowingthe LCM objects in the wellbore to the loss circulation zone.

At block 704, the method includes flowing wellbore fluid from thewellbore through the permeable portions into the subterranean formation.The motive force for flow of the wellbore fluid may be pressuredifferential with wellbore pressure greater than pressure of thesubterranean formation.

At block 706, the method includes collecting solids from the wellborefluid onto the LCM objects to stop or reduce flow of the wellbore fluidthrough permeable portions into the subterranean formation. For thepermeable portions having pores, the solids may be larger than thepores.

At block 708, the method may include producing hydrocarbon from thesubterranean formation. The producing of the hydrocarbon may involveflowing the hydrocarbon from the subterranean formation through thepermeable portions into the wellbore. The flowing of the hydrocarbonthrough the pores may dislodge the solids collected onto the permeableportions of the LCM objects.

FIG. 8 is a method 800 of applying LCM to a wellbore in a subterraneanformation. The LCM includes LCM objects that may be, for example,polymer or metal.

At block 802, the method includes pumping a slurry having base fluid,LCM objects, and solids into the wellbore to a loss circulation zone inthe wellbore. The base fluid may be, for example, drilling fluid or acarrier fluid. The LCM objects each have a porous section(s). The LCMobjects may each generally have multiple porous sections. Each LCMobject of the LCM objects may have a solid body (e.g., cuboid shape)having the porous section(s) embedded therein. The porous section(s) maybe exposed to external of the solid body.

At block 804, the method includes allowing the LCM objects to arrange(e.g., randomly) in the wellbore at the subterranean formation at theloss circulation zone. The porous section of each LCM object of the LCMobjects may be multiple porous sections disposed in respective groovesof the LCM object. Some of the porous sections may intercouple in thearrangement for fluid flow there through.

At block 806, the method includes flowing the base fluid from thewellbore through the porous section(s) of at least some of the LCMobjects into the subterranean zone. In certain examples, the poroussection of each LCM object of the LCM objects have at least five poroussections spaced apart with respect to each other

At block 808, the method includes collecting the solids on the LCMobjects to form a flow barrier to reduce or prevent loss circulation atthe loss circulation zone. The porous sections may have pores, andwherein the pores are smaller than the solids.

At block 810, the method may include producing hydrocarbon from thesubterranean formation, wherein producing the hydrocarbon involvesflowing the hydrocarbon from the subterranean formation through poroussection(s) of the LCM objects into the wellbore. The hydrocarbon flowthrough the porous section(s) may displace at least a portion of thesolids collected on the LCM objects.

An embodiment is a method of applying LCM to a wellbore in asubterranean formation, the method including: pumping a slurrycomprising base fluid, LCM objects, and solids into the wellbore to aloss circulation zone in the wellbore, the LCM objects each comprising aporous section; allowing the LCM objects to arrange in the wellbore atthe subterranean formation at the loss circulation zone; flowing thebase fluid from the wellbore through the porous section of at least someof the LCM objects into the subterranean zone; and collecting the solidson the LCM objects to form a flow barrier to reduce or prevent losscirculation at the loss circulation zone. Each LCM object of the LCMobjects may include a solid body having the porous section, wherein thesolid body includes a cuboid shape having the porous section embeddedtherein, and wherein the porous section is exposed to external of thesolid body. The porous section of each LCM object of the LCM objects mayinclude multiple porous sections disposed in respective grooves of theLCM object, and wherein the LCM objects include polymer or metal. Inimplementations, the porous section of each LCM object of the LCMobjects is at least five porous sections spaced apart with respect toeach other, wherein the five porous sections have pores, and wherein thepores are smaller than the solids. The method may include producinghydrocarbon from the subterranean formation, wherein producing thehydrocarbon involves flowing the hydrocarbon from the subterraneanformation through the porous section into the wellbore, and whereinflowing the hydrocarbon through the porous section displaces at least aportion of the solids collected on the LCM objects.

Another embodiment is a plurality of LCM objects, each LCM object of theplurality having a solid body (e.g., cuboid shape) having permeablesections including pores, wherein the plurality of LCM objects toarrange at a loss circulation zone in a wellbore in a subterraneanformation to initially allow wellbore fluid to flow through the poresinto the subterranean formation, and the plurality of the LCM objects tocollect solids from the wellbore fluid to form a flow barrier. Theplurality of LCM objects as arranged to intercouple permeable sectionsamong the plurality at the loss circulation zone, and wherein the poresare smaller than the solids. The plurality of LCM objects may be flakyLCM. Each LCM object of the plurality may be polymer or metal. Inimplementations, each LCM object of the plurality has at least fivepermeable sections. The plurality of LCM objects may include a first setof the LCM objects having a first orientation of the permeable sections,and a second set of the LCM objects having a second orientation of thepermeable sections different than the first orientation. The LCMpermeable sections of the solid body of each LCM object of the pluralitymay be disposed at are near an external surface of the solid body. Thepermeable sections may be elongated and have depth into the solid body.In some implementations, the solid body has a length less than 30 mm, aheight less than 10 mm, and a width less than 10 mm. The permeablesections of the solid body of each LCM object of the plurality may bespaced apart. The plurality of LCM objects may be fabricated by additivemanufacturing (3D printing).

Tables 1-4 below give Examples of treatment fluids that may deploy thepresent LCM (e.g., FIGS. 1-4). The present LCM can be shaped LCM havingpermeable sections. The treatment fluids (Tables 1-4) are indicated asdrill-in fluids and may be altered at least with respect toincorporating the present LCM. While drill-in fluid is noted, treatmentfluids as indicated in Tables 1-4 may be drilling fluid more generallyor a carrier fluid. The treatment fluids may have an aqueous fluid phaseor a non-aqueous fluid phase. The aqueous phase can be fresh water,monovalent salt water, or divalent salt water, and so forth. Thenon-aqueous phase can be, for example, mineral oil or synthetic oil, andthe like. As indicated in Tables 1-4, Examples of the treatment fluid(e.g., drill-in fluid) can include a viscosifier, a fluid loss additive,and calcium carbonate (CaCO3). The CaCO3 can be granular as coarseparticles (C), medium particles (M), or fine particles (F), or anycombinations thereof. The viscosifier can be, for instance, apolysaccharide (e.g., xanthan gum or XC polymer), a carboxymethylcellulose (CMC), or a cellulose derivative (e.g., polyanionic celluloseor PAC), or any combinations thereof. The fluid loss additive can be,for example, starch, psyllium husk powder, or a polyanionic cellulosepolymer (e.g., PAC LV™ available from AMC Drilling Optimisation ofBalcatta, Western Australia, Australia), or any combinations thereof.The present LCM (e.g., shaped LCM with permeable sections) can be, forexample, 10-30 pounds/barrel of the altered drill-in fluid. The units inTables 1-4 below are cubic centimeter (cc) or grams (g). The volumes ofthe water (fresh water or salt water) (Tables 1-3) are given as areference basis with respect to the associated remaining components inthe given Table. The volumes of the oil (mineral oil or synthetic) inTable 4 are given as a basis with respect to the associated remainingcomponents in Table 4.

TABLE 1 Fresh Water-Based Altered Drill-In Fluid System ComponentsQuantity Range Fresh Water (cc) 331 250-400  XC Polymer (g) 1.5 0.5-3.5 Modified Starch (g) 6 2-10 Biocide (cc) 0.5 <1 NaOH (g) 0.3 <0.8 CaCO3,F (g) 20 5-40 CaCO3, M (g) 10 3-30 CaCO3, C (g) 5 <10 Shaped LCMs with15 5-40 Permeable Sections (g)

TABLE 2 Monovalent Salt Water-Based Altered Drill-In Fluid SystemComponents Quantity Range Water (cc) 296 220-380  NaCl (g) 75 50-100 XCPolymer (g) 1.5 0.5-3.5  Modified Starch (g) 6 2-10 Biocide (cc) 0.5 <1NaOH (g) 0.3 <0.8 CaCO3, F (g) 20 5-40 CaCO3, M (g) 10 3-30 CaCO3, C (g)5 <10 Shaped LCMs with 15 5-40 Permeable Sections (g)

TABLE 3 Divalent Salt Water-Based Altered Drill-In Fluid SystemComponents Quantity Range Water (cc) 287 200-350  CaCl₂ (g) 100 50-150XC Polymer (g) 1.5 0.5-3.5  Modified Starch (g) 6 2-10 Biocide (cc) 0.5<1 NaOH (g) 0.3 <0.8 CaCO3, F (g) 20 5-40 CaCO3, M (g) 10 3-30 CaCO3, C(g) 5 <10 Shaped LCMs with 15 5-40 Permeable Sections (g)

TABLE 4 Non-Aqueous Drill-In Fluid System (Mineral Oil or Synthetic Oil)Mineral Oil- Mineral Oil- Synthetic Oil- Synthetic Oil- Components BasedMud Based Mud Based Mud Based Mud Base Oil (cc) 186 150-220  186150-220  Invermul (cc) 10 5-15 10 5-15 EZ-mul (cc) 6 <10 6 <10 Lime (gm)5 <9 5 <9 Viscosifier (g) 6 2-10 6 2-10 Fluid Loss 7 3-12 7 3-12Additive (g) Water (cc) 84 50-120 84 50-120 CaCl₂ (g) 61 20-100 6120-100 CaCO₃ F (g) 25 10-40  65 40-90  CaCO₃ M (g) 20 5-35 65 40-90 CaCO₃ C (g) 15 3-30 65 40-90  Shaped LCMs 15 5-25 15 5-25 with PermeableSections (g)

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made without departingfrom the spirit and scope of the disclosure.

What is claimed is:
 1. A lost circulation material (LCM) comprising aplurality of LCM objects, each LCM object of the plurality comprising asolid body having permeable sections comprising pores, wherein theplurality to arrange at a loss circulation zone in a wellbore in asubterranean formation to allow wellbore fluid to flow through the poresinto the subterranean formation, and the plurality to collect solidsfrom the wellbore fluid to form a flow barrier.
 2. The LCM of claim 1,wherein each LCM object of the plurality comprises polymer or metal, andwherein the solid body of each LCM object of the plurality comprises atleast five permeable sections.
 3. The LCM of claim 1, wherein theplurality comprises: a first set of the LCM objects comprising a firstorientation of the permeable sections; and a second set of the LCMobjects comprising a second orientation of the permeable sectionsdifferent than the first orientation.
 4. The LCM of claim 1, wherein thepermeable sections of the solid body of each LCM object of the pluralityare disposed at are near an external surface of the solid body, andwherein the permeable sections each comprise a length greater than theirwidth and comprise depth into the solid body.
 5. The LCM of claim 1,wherein the solid body of each LCM object of the plurality comprises acuboid shape.
 6. The LCM of claim 1, wherein the solid body of each LCMobject of the plurality of LCM objects is fabricated by additivemanufacturing comprising three-dimensional (3D) printing, and whereinthe solid body comprises a length less than 30 millimeters (mm), aheight less than 10 mm, and a width less than 10 mm.
 7. The LCM of claim1, wherein the permeable sections of the solid body of each LCM objectof the plurality are spaced apart on each LCM object, wherein theplurality as arranged to intercouple permeable sections among theplurality at the loss circulation zone, and wherein the pores aresmaller than the solids.